This invention relates to a multilayer composite sheet having one layer of an acrylonitrile-butadiene-styrene or ABS type polymer and adjacent layers of thermoplastic resin.
Multi-layer material systems which combine the positive properties of two or more different materials are known. Ideally, the materials are combined with the integrity of each material being essentially uncompromised. Although many of these multilayers can be hypothesized on the basis of laminating a material possessing certain strong properties with a material having strong properties in other areas, certain practical considerations inhibit successful implementation of this theory. The two materials are in intimate contact at their interface. The compatibility of the two resins at this interface is generally not known until actually contacted at the high temperatures necessary to obtain adherence of the two layers. Where incompatibility is significant, for example the two layers pull apart with little external stressing force, a tie layer that binds the two relatively incompatible layers is necessary. In general, polymers of significantly differing chemical structure are relatively incompatible and require a tie layer for many of the structure""s applications.
It is desirable to combine certain polymers with significantly differing chemical structures adjacent to each other in a multilayer composition without the benefit of a tie layer.
U.S. Pat. 4,737,414 to Hirt et al describes a multilayer composite wherein a layer comprising an aromatic polyetherimide is adjacent to a layer comprising an aromatic polyester. A tie layer of a copolyestercarbonate is described.
A multi-layered composite includes an acrylonitrile-butadiene-styrene (ABS) layer in direct contact with an adjacent thermoplastic resin layer wherein the respective layers include less than a foaming amount of reactive metal oxides. The adjacent resin layer preferably comprises polycarbonate resin, phenylene ether resins, and polyamides.
It is highly desirable that the adjacent layers be compatible so that the layers adhere. It is desirable to avoid ingredients in one layer that might react with the ingredients in the other layer. A typical foaming reactive metal oxide is magnesium oxide. The above layers are compatible and are characterized by the absence of reactive materials such as some metal oxides such as magnesium oxide.